Topic: Terry's Kawasaki Mach III 500 build. Let the smoke begin.....

[Terry in Australia]

Thanks Per, how much do you pay to have your cylinders bored? Last time I asked a shop it was around $150 ($100 USD) per cylinder for just the next oversize, but a lot more for hogging them out 4mm for 836 kits.

The “method in my madness” for setting up my boring bar for multi cylinder bikes is that apart from my own jobs, I’ll offer my services to other CB750 and Z1 etc owners here in Oz who are restoring/hot rodding their bikes for a little extra tax free dough in my retirement.

Shops that offer cylinder boring are becoming harder to find, so I might get some work out of it. I’m also thinking about buying a vapor blasting setup, that way I can blast cylinder blocks back to “as new” before I bore them, and as I have an AC/DC TIG welder I’ll do fin repairs as well. I don’t expect to spend my retirement just working on bikes, but a little bit here and there would be nice.

[PeWe]

Bore price was closer to $200US. 0.5mm or 1mm same cost.
Other shops in other cities take 250.

My 970 included removal of old stock sleeves. Bore cylinder for CycleX 74.5mm sleeves.
Mill down the cylinder 1mm to match piston heights.
Mill 1mm for sleeve flanges and for 2 o-rings.
Crimp on the sleeves. Bore and hone the 69mm sleeves to 70mm (total piston clearance 0.05mm, forged JE pistons)

Calculate how much of the piston crowns to mill off to get right compression with the head 23.6cc chambers.

Pistons were 12.5:1.
Milled off ca 3mm.
All that not that much, maybe $450US.

But I have let him to do a few bore jobs, guide replacements and port jobs the last years.

Other shops should charge me for every minute and more.
I do not know a shop I should trust within 100km radius.
Ship parts will add risks and huge costs.

[HondaMan]

The first big job will be to bore another cylinder block to take some 970cc sleeves, that should be a good test of my measuring skills as I need to bore the block slightly undersize so that the sleeves will be a tight fit once I've heated the block to install them. Isn't backyard engineering fun?
 

I envy you that toy!
Here's a hint from the local machine shop: they said the holes in the block should be 0.001" (1 thousandth of an inch) smaller than the outside of the sleeves.
I don't know how many AUS microns that is, maybe one of those Malaysian math gurus could translate it?

[Terry in Australia]

Ha ha, thanks Mark, I have both metric and historical micrometers here, but I do appreciate that info, the last thing I want to do is insert the sleeve ok when the block has been heated in my industrial oven then have it crack when it cools down.

[PeWe]

There are several converters on Internet.
Just search inch vs mm.

Here is one
https://www.rapidtables.com/convert/length/inch-to-mm.html?insel=u&fracsel=u&f=&x=0.001&n=&d=

0.001" = 0.0254mm

I often convert  ft lbs to Nm.
Find converter by searching ft lbs vs Nm
Temp: F vs C
Etc etc....

I could not resist to search about sleeve vs bore size for get proper crimp.
Not an exact answer here but seal the lower part is vital to avoid leaks it WILL leak between 1-2 and/or 3-4 if not sealing the sleeves-cylinder.

https://www.techshopmag.com/tech-feature-cylinder-sleeve-installation-procedures/

My 970 cylinder got its lower part bored +2.5mm wider for a groove of 1.25mm wide, 5-6mm deep for an o-ring with tight fit + Hondabond on top between sleeves and cylinder.

Sleeves from CycleX, 74.5mm OD so there were meat around for this groove.

O-ring 65x1.5mm that stretched perfectly into the 74.5x1.25mm groove with tight fit.

[RAFster122s]

0.001" shoot that's easy Mark, that's just two kangaroo hairs thick...
Terry just needs to take a ride in the country at night and hit a roo like Eric did of the fawn to get a sample of roo hairs on the front wheel and rim.
All for the low low price of a side reflector on a fork.

Don't worry mate, the roo will understand and cooperate I'm sure...
May wanna wear leather pants and jacket in case the joey doesn't read the thread in time...


(Joking, in case it wasn't obvious.)
How did you adjust your boring bar to get precision measurements?
Have you made a jig that has fine precision screws to dial in the diameter/length of the cutting head to serve as a gauge? Or is it a set it measure and repeat until you get the required measurement?

[MauiK3]

You can shrink the sleeves too.
Isopropyl alcohol in a little metal bucket big enough for the sleeves, have Everything ready, drop some dry ice in the alcohol and watch it change to a thick consistency. Let them cool in the bucket and they will fall in if all there is is .001” interference.
I forget what temp the alcohol gets too.
Maybe insulate the bucket to help.
This trick works for bearing races like a champ.

[Terry in Australia]

Thanks guys. The boring bar came with a special micrometer for measuring the cutter, but over it's life it's probably been used as a hammer and so I bought another one from India for a Van Norman machine, but the cutters aren't a good fit. (I thought mine was a Van Norman, but it's actually an Australian made "Repco" brand machine, so everything is slightly different. I get away with using a digital vernier, and as I can only do small cuts (20 thou) per pass, I can usually get the bores to be tight for each piston, then hone them to around 2 thou clearance for cast, or a tad more for forged pistons.

I've just ordered a nice bore gauge with micrometer head, so when it arrives I'll continue to bore those cylinders I posted a pic of, and see how good of a job I can make to suit some "barely used" first oversize pistons. I'm also building a honing machine using an old lightweight drill press in a big plastic tub with a sliding "carrier" for the cylinder block, with a 12V fluid pump so I can hone away to my hearts content "mess free", with a new 4 stone hone I've also ordered, as my old "Ammco" 4 stone hone is getting a bit tired after 50 or 60 years of service. I'll post some pics and a short vid once I've finished building it, but I did a trial run on Monday before flying out to Canberra, and am happy with the concept. More soon.    

[grcamna2]

Yeah,I'd like to see the video Terry.

[HondaMan]

I can usually get the bores to be tight for each piston, then hone them to around 2 thou clearance for cast, or a tad more for forged pistons.

Yikes! You're scarin' me!
The 750, up to 836cc (65mm bore) should have pistons clearance no more than 0.0012". I usually set them to 0.0008" up to 4th oversize. I do the 65mm versions at 0.0010" (both after honing).

[Terry in Australia]

Thanks Mark, there aren't too many cylinder borers here who'll bore an air cooled engine less than .002", and they recommend a bit more for forged pistons. I'm not talking about OEM pistons here, I haven't seen a shiny new OEM Honda piston since 1981 when I first used this same boring bar to bore my K1 out to first O/S after it seized due to oil starvation to the head. (I think from memory the clearance we were happy with was around 0015".

I don't think I'm going to have any problems though, here's a link to LA Sleeve's specs for boring their cylinders (standard cast iron, just like Honda's) that looks like I might be boring my engines about right.

https://www.lasleeve.com/downloads/piston-clearances.pdf

[grcamna2]

I can usually get the bores to be tight for each piston, then hone them to around 2 thou clearance for cast, or a tad more for forged pistons.

Yikes! You're scarin' me!
The 750, up to 836cc (65mm bore) should have pistons clearance no more than 0.0012". I usually set them to 0.0008" up to 4th oversize. I do the 65mm versions at 0.0010" (both after honing).

+1

[HondaMan]

Thanks Mark, there aren't too many cylinder borers here who'll bore an air cooled engine less than .002", and they recommend a bit more for forged pistons. I'm not talking about OEM pistons here, I haven't seen a shiny new OEM Honda piston since 1981 when I first used this same boring bar to bore my K1 out to first O/S after it seized due to oil starvation to the head. (I think from memory the clearance we were happy with was around 0015".

I don't think I'm going to have any problems though, here's a link to LA Sleeve's specs for boring their cylinders (standard cast iron, just like Honda's) that looks like I might be boring my engines about right.

https://www.lasleeve.com/downloads/piston-clearances.pdf

I haven't used the Pro-X pistons, so I can't speak to those gizmos (don't know their composition?). With the standard cast-and-machined aluminum pistons we see the most for these engines, the tighter is far better. I've 'miraculously' fixed many engines that were supposedly "built for racing" that were low-power, non-revving mosquito foggers with constatnly-fouled sparkplugs and oily exhausts by just boring to the next oversize with less than 0.0010" clearance. None of these, though were bigger than 70mm bores, either, except the 450 Twins: those get 0.0018" from this miser.

[MauiK3]

It’s amazing that the clearance works in an air cooled engine. Great engineering

[grcamna2]

Thanks Mark, there aren't too many cylinder borers here who'll bore an air cooled engine less than .002", and they recommend a bit more for forged pistons. I'm not talking about OEM pistons here, I haven't seen a shiny new OEM Honda piston since 1981 when I first used this same boring bar to bore my K1 out to first O/S after it seized due to oil starvation to the head. (I think from memory the clearance we were happy with was around 0015".

I don't think I'm going to have any problems though, here's a link to LA Sleeve's specs for boring their cylinders (standard cast iron, just like Honda's) that looks like I might be boring my engines about right.

https://www.lasleeve.com/downloads/piston-clearances.pdf

I haven't used the Pro-X pistons, so I can't speak to those gizmos (don't know their composition?). With the standard cast-and-machined aluminum pistons we see the most for these engines, the tighter is far better. I've 'miraculously' fixed many engines that were supposedly "built for racing" that were low-power, non-revving mosquito foggers with constatnly-fouled sparkplugs and oily exhausts by just boring to the next oversize with less than 0.0010" clearance. None of these, though were bigger than 70mm bores, either, except the 450 Twins: those get 0.0018" from this miser.

I'm glad I found a Powersports machinist who bores and hones my piston to cylinder clearances 'to the factory specs' fit. I like the longevity of the bore job and the compression is great 

[Terry in Australia]

Thanks Mark, there aren't too many cylinder borers here who'll bore an air cooled engine less than .002", and they recommend a bit more for forged pistons. I'm not talking about OEM pistons here, I haven't seen a shiny new OEM Honda piston since 1981 when I first used this same boring bar to bore my K1 out to first O/S after it seized due to oil starvation to the head. (I think from memory the clearance we were happy with was around 0015".

I don't think I'm going to have any problems though, here's a link to LA Sleeve's specs for boring their cylinders (standard cast iron, just like Honda's) that looks like I might be boring my engines about right.

https://www.lasleeve.com/downloads/piston-clearances.pdf

I haven't used the Pro-X pistons, so I can't speak to those gizmos (don't know their composition?). With the standard cast-and-machined aluminum pistons we see the most for these engines, the tighter is far better. I've 'miraculously' fixed many engines that were supposedly "built for racing" that were low-power, non-revving mosquito foggers with constatnly-fouled sparkplugs and oily exhausts by just boring to the next oversize with less than 0.0010" clearance. None of these, though were bigger than 70mm bores, either, except the 450 Twins: those get 0.0018" from this miser.

Thanks Mark, there aren't too many cylinder borers here who'll bore an air cooled engine less than .002", and they recommend a bit more for forged pistons. I'm not talking about OEM pistons here, I haven't seen a shiny new OEM Honda piston since 1981 when I first used this same boring bar to bore my K1 out to first O/S after it seized due to oil starvation to the head. (I think from memory the clearance we were happy with was around 0015".

I don't think I'm going to have any problems though, here's a link to LA Sleeve's specs for boring their cylinders (standard cast iron, just like Honda's) that looks like I might be boring my engines about right.

https://www.lasleeve.com/downloads/piston-clearances.pdf

I haven't used the Pro-X pistons, so I can't speak to those gizmos (don't know their composition?). With the standard cast-and-machined aluminum pistons we see the most for these engines, the tighter is far better. I've 'miraculously' fixed many engines that were supposedly "built for racing" that were low-power, non-revving mosquito foggers with constatnly-fouled sparkplugs and oily exhausts by just boring to the next oversize with less than 0.0010" clearance. None of these, though were bigger than 70mm bores, either, except the 450 Twins: those get 0.0018" from this miser.

Thanks Mark, there aren't too many cylinder borers here who'll bore an air cooled engine less than .002", and they recommend a bit more for forged pistons. I'm not talking about OEM pistons here, I haven't seen a shiny new OEM Honda piston since 1981 when I first used this same boring bar to bore my K1 out to first O/S after it seized due to oil starvation to the head. (I think from memory the clearance we were happy with was around 0015".

I don't think I'm going to have any problems though, here's a link to LA Sleeve's specs for boring their cylinders (standard cast iron, just like Honda's) that looks like I might be boring my engines about right.

https://www.lasleeve.com/downloads/piston-clearances.pdf

I haven't used the Pro-X pistons, so I can't speak to those gizmos (don't know their composition?). With the standard cast-and-machined aluminum pistons we see the most for these engines, the tighter is far better. I've 'miraculously' fixed many engines that were supposedly "built for racing" that were low-power, non-revving mosquito foggers with constatnly-fouled sparkplugs and oily exhausts by just boring to the next oversize with less than 0.0010" clearance. None of these, though were bigger than 70mm bores, either, except the 450 Twins: those get 0.0018" from this miser.

I haven’t used “Pro-X” piston’s either Mark, but plenty of Wiseco’s, did you see their recommendations at the bottom of the page? 65mm pistons - 0025”.

[PeWe]

That is for forged pistons, my JE pistons have same recommendation from Dynoman.
Check their tech page for their pistons. Good info where also ring gap orientation is shown in a good way.
http://dynoman.net/tech-sheets.html

My CI +0.50mm pistons got 0.02mm (0.00078") total clearance. (It takes almost no oil between 4500km oil change interval. Maybe level get 5mm lower on dipstick.)

I read on this forum about max 0.025mm (0.00098") to avoid being a smoker. I think it was the UK guys that have great experiences of CI piston rebuilds.

My K2 first had CI stock size 61.00 mm in only honed old bores, 0.04-0.05mm (0.000157-0.000196") clearance.
It smoked fine all the time so not only early ex guides without seals. Other riders behind me complained when riding 120-140kmh on highway

My old 836 cylinder that was bored and later honed several times more.

First was bored to RC forged pistons (these were slimmer to wider clearance), 8000km later new cast Action Fours, 40000 km later NOS RC cast pistons. It did not smoke despite clearances well over 0.15mm, some spots 0.20mm toral clearance.
I watched it on Dyno when revved it to over 9000rom several times, last run 10.000rpm. No smoke and rods still OK